President of the Catalan Government Carles Puigdemont leaves following an institutional declaration after signing a decree calling independence referendum at the Catalan Parliament in Barcelona, Spain, September 6, 2017. (AFP photo)

The Constitutional Court of Spain has suspended another referendum law ratified in the regional parliament of Catalonia as Madrid struggles to block a vote of independence in the region planned for earlier next month.

The court, which serves as the highest Spanish authority on constitutional issues, said on Tuesday that the law outlining a legal framework for the October 1 referendum of independence in Catalonia would be suspended until judges decide its compliance with the Spanish constitution.

The Catalonia parliament had approved the law on September 6 along with another decision to endorse the referendum itself. The Constitutional Court in Madrid had earlier suspended the first law and warned that it would punish civil servants contributing to the vote in any form.

The court ruling comes just a day after hundreds of thousands marched in the streets of Barcelona, Catalonia’s capital, to declare their support for the independence vote. Regional leaders have sought to use the massive rally, held on Catalonia’s national day, as a sign of rising inclinations in the region to split from Spain.

This handout picture released on September 11, 2017 by the Assemblea Nacional Catalana (Catalan National Assembly) shows an aerial view of people waving a giant banner reading in Catalan “Independence now” during a pro-independence demonstration, on September 11, 2017 in Barcelona during the National Day of Catalonia, the “Diada.” (AFP photo)

Recent polls suggest that support for the secession has been waning but a majority of people still want the referendum to decide on the issue once and for all. The central government in Madrid also insists that the vote is illegal as the constitution clearly stipulates that Spain is indivisible. Authorities have also filed criminal charges against Catalan leader Carles Puigdemont, among other officials, saying he was only authorized to call an election not a referendum.

“If Puigdemont wants to consult the people, it’s very simple, he should call an election,” said Inigo Mendez de Vigo, Spain’s minister of education, culture and sport, who also serves as the government spokesman.

Puigdemont, however, has vowed that his government would go ahead with the planned referendum. The regional leader is allowed to declare independence from Spain within 48 hours of a “yes” vote, even if it is the result of a low turnout.